1. Field of the Invention
The present invention relates to memory card connector assemblies, and particularly to a dual IC package connector assembly which has a pair of similar connectors stacked together for reception of two IC memory cards, respectively.
2. Description of the Prior Art
IC packs or memory cards are used in a variety of electronic equipment, especially in laptop, palmtop, even notebook computers. The reason is that memory cards have recently been developed to improve memory capabilities in computer system and their modularity, increased memory capacity and smaller physical dimensions make them particularly desirable, especially in small-sized computer. Some prior art devices can be referred to U.S. Pat. Nos. 5,176,523, 5,161,989, 5,152,697, 5,051,101, 5,149,276, 5,145,389, 5,139,435, 5,011,420, 4,952,161 and 4,810,200.
As disclosed in aforementioned U.S. Pat. No. 5,149,276 to Dixon, it is desired to have a array of cards for saving space, so that a plurality of the devices may be stacked one upon the other with sufficient spacing allowed for operation. Also, in aforementioned U.S. Pat. No. 5,176,523 to Lai, which has the same assignee as the present invention, teaches mechanism able to reduce the whole height when a plurality of memory card connectors are aligned and stacked together.
Even though the stacked type connector assemblies are more space efficient, another problem may occur about the alignment of the upper connector contacts with the corresponding conductive circuit traces positioned on the main board on which the connector assembly is seated because there is a significant vertical distance between the horizontal position of the upper connector contact and the main board. It can be seen that the vertical tail portions of such upper connector contacts may easily obliquely extend downwardly due to shortness of support means in the vertical direction. This situation becomes serious when the tails of the upper connector contacts are required to extend a distance in the horizontal direction for corresponding to the printed circuit layout of the main board on which the connector assembly is seated. This disadvantage may also get worse when this connector assembly is used in surface mount soldering instead of through-hole soldering because through-hole mounting of the contact with the board allows a relative larger range of manufacturing tolerance than surface mount type based on self-adjustment of the former. In other words, unlike the through-hole contact, a misaligned surface mount type contact can not be correctly and exactly mounted to the corresponding circuit trace, thus affecting the soldering between the contact and the trace, and perhaps resulting in missing signals during transmission.
To solve this problem, an attempt has been made by using a flat cable connectively incorporating two Insulative Displacement Contact (IDC) connectors respectively positioned on the main board and the rear of the upper connector for connection of the upper connector contacts, which are of a short tail type, and the main board, instead of the prolong tails of the upper connector contacts extending between the main board and the upper connector. Although this type solution can prevent misalignment problem between the upper connector contacts and the board traces, those three additional components need more manual operative assembling and the flat cable intends to take more space and swing up and down. This configuration obstructs miniaturization and automation in product development, and makes the manufacturing process more complex.
Accordingly, it is desired to have a device which includes relatively compact and secure components but still achieves the same function, i.e., the alignment of the upper connector contacts with the main board on which the connector assembly is seated.
An object of the present invention is to provide means which are easily and matably connected to either the upper connector or the lower connector, and are adapted to efficiently align the tails of the upper connector contacts with the traces printed on the board on which the connector assembly is seated.
Another object of the present invention is to provide a low profile IC memory card connector regardless of single or stacked dual type. The reason why the whole thickness can be reduced is partially due to the structure that the ejection mechanism is disposed above and proximate the housing body instead of below the inserted card as shown in most prior art memory card connectors.
Yet an object of the present invention is to provide a connector assembly which allows three different type existing cards selectively to be used therewith. Moreover, each single connector can be individually utilized to be mounted on the main board with another upper connector on its top. All connectors can be made by one mold and have the same structure for mass production and lowering the cost.
Further, an object of the present invention is to provide a connector assembly, regardless of single connector or two stacked connectors, with a grounding path for ESD protection.